Fuel control



Aug. 12, 1924. 1,504,724

H. F. SCHMIDT FUEL CONTROL Filed Jan. 5, 1921 2 She'ets-Sheet l fiknrfljaiizidi WlTNESSES: INVENTQR ATTORNEY Aug. 12, 1924. 1,504,724

H. F. SCHMIDT FUEL CONTROL Filed JQH- 1,921 2 Sheets-Sheet 2 ATTORNEY Patented Aug. 12, 1924.

UNITED STATES PATENT OFFICE.

HENRY F. SCHMIDT, OF SWARTHMORE, PENNSYLVANIA, ASSIGNOR TO WESI ING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

FUEL CONTROL.

Application filed January 3, 1921.

To all whom a may concern:

Be it known that I, HENRY F. SCHMIDT,

I a citizen of the United States, and a resident of Swarthmore, 1n the county of Delaware and it has for its object to provide an apparatus of the character designated whereby the admission of steam to the prime movers of fuel-feeding and draft-regulating devices is controlled directly by the rate of flow of p boiler feed water supply and by boiler pressure.

A further object is to produce an apparatus which shall be simple in construction, positive in operation and accurate in regulation over a widerange of requirements.

These and other objects will be more manifest in the description given in the following specification and drawings, in which Fig. 1 isa diagrammaticview of apparatus constructed in accordance with my invention;

Fig. 2 is an enlarged view, partlally 111 section and partially in elevation, of a portion of the apparatus illustrated in Fig. 1, and i i Fig. 3 isa diagrammatic detail view showing the application of the regulating effect of the apparatus illustrated in Fig. 2, to an electric motor.

In the operation of power plants it is highlydesirable to obtain the greatest degree ofefliciency from the power apparatusm operation. Many attempts have been made to regulate the amount of fuel fed to the furnaces in accordance with the requirements for steam. In systems of this nature Venturi meters and Pitot tubes have been installed in the steam line leading from the boiler to the prime mover, whereupon a regulating effect is derived from variations in steam flow and pressure. These devices have been unsatisfactoryin operation for the reason that they fail to accurately regulate the amounts of heat-supplying elements necessary to maintain uniform boiler conditions. 1 have found that the quantity of heat demanded by Serial No. 434,637.

a boiler under any conditions of operation may be regulated with a high degree of accuracy coordinating the regulating effects of boiler pressure and of the rate of flow in feed water supply to the boiler. In carryng out my invention, 1 place a Venturi regulater in the feed water supply pipe adjacent to the boiler and through the agency of a diaphragm motor, regulate the quantities of heat-supply elements delivered to the boiler furnace.

My invention will be more clearly understood by referring to the drawing, wherein like reference characters indicate corre sponding parts in the different figures. As shown, 10 indicates a boilerwhich is heated by a furnace 6 of any well known construc tion, supplied with fuel by a feeding mechanism or stoker 7, and with air by a fan 8. As shown, the stoker 7 is of the well known underfeed type in which solid fuel is forced into a retort by a reciprocating ram, but it is to be understood that any suitable device for feeding solid, liquid, or gaseous fuel, may be used.

The stoker 7 and the fan 8 are driven, as shown, from an engine 9 by means of belts, but it will be obvious that other driving means, such as an electric motor 27, may be employed. Motive fluid is supplied to the engine through a conduit 17, and it is apparent that the speed of the auxiliaries 7 and 8, which control the rate of combustion in the furnace, will vary with the speed of the engine 9, which is determined by the flow of motive fluid through the conduit 17. Feed water is supplied to the boiler 10 through a conduit 11, in which is located a Venturi meter element 12 and all water fed to the boiler passes through the meter. A conduit 13 communicates with the restricted portion of the Venturi element and a similar conduit 14; communicates with the feed water conduit near the entrance of the Venturi element. A check valve 16 is located in the feed water conduit in such a manner that the Venturi element 12 and the conduits13 and 1 1 will be subject to conditions of boiler pressure under all conditions of operation. Steam is supplied to the auxiliaries which control the feed of heat-sup plying elements to the boiler furnaces through a conduit 17 in which is located a balanced valve 18. A diaphragm motor 19 portions may be determined, when the conditions of operation are known, by calculations based on the principle of the diiiierentlal piston. The flexible portions of the discs are connected at their mid portions to a eration of an electric drive motor 27. is obvious that a mechanical device for feedvalve stem of thebalanced valve 18. As shown in Fig. 2, the stem 25 may be connected to the rheostat 26 which controls the oping solid, liquid, or gaseous fuel to a furnace may readily be controlled by the stem 25. The water in the boiler 18 maintained at a constant level by the float 28 located to the lever 29.

therein. The float 28 is carried by a lever 29 pivoted at 30. A balanced valve 31, located in the feed water supply conduit 11. is operated by a stem which 13 connected Having thus described the arrangment of an apparatus constructed in accordance with my invention, the operation thereof is as follows: Assuming that the device is adjusted to operate under normal conditions of 100 lbs. steam pressure, under these conditions 100 lb. pressure will be exerted in the conduit 11 which will transmit the steam pressure to the conduits 13 and 1a which, in turn,

transmit static pressure to both compartments of the diaphragm pressure motor 19.

It will be observed by the ratios of the areas of the flexible diaphragms 22, 23 and 24, that the resultant pressures will hold the valve stem 25 to permit a predetermined amount of steam to pass the valve 18. As

suming that the stoker mechanism 9 will operate at a normal rate with 100 lb. steam pressure, the steam pressure rises and it will be observed that the stem 25 will tend to close the valve 19 still further and thus tend to lessen the speed of the stoker feeding mechanism, or as shown in Fig. 3 by di minishing the current of the motor 27. On

a the other hand, assuming that there is a drop in steam pressure, the tendency of the stem 25 will be upward, thereby allowing an increased supply of steam to the heat-control mechanisms and thus a stimulation in the heat supply auxiliaries. Itwill be observed that I have further provided a float 28 in the boiler 10 arrangedto maintain the water level within the boiler approximately constant and any lowering of the water level 1 within the boiler will cause thefloat 28 to lower and thereby raise the balanced valve 31, which is located within the feed water supply conduit 11, and allow feed water under pressure to flow to the boiler 10, through the check valve 16 and the Venturi meter 12.

In thus supplying boiler feed water to the boiler, I accomplish a further regulating effect. The feed water, in passing the throat 12 of the Venturi element, creates a reduced pressure inthe conduit 13 and acorresponding reduction of pressure results in the chamber 20 of the pressure diaphragm motor device 19. It will be observed, from the ratios of the areas of the flexible discs 22, 23 and 24, that the tendency of movement will be upward, thereby opening the balanced valve 18 and increasing the amount of motive fluid to the heat producing auxiliaries. The operation of the device in the above manner provides for the usual drop in steam pressure attended by the feeding of cold water to the boiler by opening the valve 18 and stimulating the heat supplying agencies in accordance with the rate at which feed water is fed to the boiler.

lVhile I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various other changes and modifications, without departing from the spirit thereof and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

lVhat I claim is:

1. The method herein described of controlling combustion in furnaces which consists in regulating the supply of fuel in accordance with the boiler pressure and further varying the feed of said fuel in accordance with variations in the rate of feed water supply.

2. The method herein described of controlling combustion in furnaces which consists in regulating the feed of fuel in accordance with the boiler pressure and in further varying the supply of said fuel in accordance with the combined effect of variations in boiler pressure and the rate of feed. water supply.

3. The method herein described of controlling combustion in furnaces which consists in regulating the supply of air to the combustion chamber of a furnace in accordance with changes in boiler pressure and rate of feed water supply.

4. The method herein described of controlling combustion in furnaces which consists in utilizing changes in boiler pressure in conjunction with pressure changes occasioned by the rate of feed water supply to regulate fuel and air supply to the furnace, and varying the rate of such supply by and in accordance with the rate of flow of feed water to the boiler.

5. In a boiler regulator, the method of regulating the heat supply to the boiler, which comprises combining a regulating eflect derivable from the boiler pressure and a regulating eiiect derivable from the rate oi feed Water supply to the boiler to vary the rate of combustion of fuel by Which heat is supplied thereto. v

6. In a boiler regulator, the method of regulating the heat supply to the boiler which comprises supplying a motive fluid to the prime mover of a heat producing element, and regulating the quantity of said fluid so supplied in response both to the changes of pressure inthe boiler and changes in rate of feed Water supply tothe boiler.

7. In a heat regulating mechanism for boiler furnaces, a boiler, a feed Water pipe delivering Water to the boiler and pressure means responsive to the combined conditions of velocity flow through the feed Water pipe and pressure Within the boiler for increasing the intensity of the furnace heat, both upon an increased flow of feed Water and upon a decrease in boiler pressure.

8. In a heat regulating mechanism for boiler furnaces, a boiler, a feed Water pipe delivering Water to the boiler, pressure means responsive to the combined conditions of velocity flow through the feed Water pipe and pressure Within the boiler for increasing the intensity of the furnace heat both upon an increased flow of feed Water and upon a decrease in boiler pressure, and float controlled means for maintaining the quantity of feed Water Within the boiler substantially constant.

9. In a heat regulating mechanism for boiler furnaces, a boiler, a feed Water pipe delivering Water to the boiler, a diaphragm motor device connected to the feed-Water pipe and responsive to the combined conditions of velocity flow through the feed Water pipe, and pressure Within the boiler for increasing the intensity of the furnace heat upon an increased flow of feed Water and decreased pressure Within the boiler.

In testimony whereof, I have hereunto subscribed my name this 29th day of December, 1920.

HENRY F. SCHMIDT. 

